This invention relates generally to synthesis gas, or syngas, coolers for use in a gasifier system, and, more specifically, to a quench system for use with a syngas cooler.
Some known gasification systems use two syngas coolers in series to cool syngas, slag, and fly ash particles contained therein. Such systems can be used advantageously because, typically, a first syngas cooler, typically a radiant syngas cooler, or RSC, incorporates slag and fly ash separation and quenching means near a first syngas outlet that facilitates reducing the potential of fouling and plugging in a second syngas cooler. Fouling and plugging is a concern associated with the second syngas cooler, typically a convective syngas cooler, or CSC, due to changes in heat transfer surface materials and configurations that are used to effectively transfer heat, as well as changing flow conditions. Such a series cooler arrangement facilitates heat transfer efficiency, however, a large capital investment in such a two syngas cooler arrangement may not always be cost-effective. Furthermore, under certain circumstances, such an arrangement may not effectively mitigate fouling and plugging.
Some other known gasification systems use a first syngas cooler similar to that described above, but unlike the arrangement described above, exclude the second syngas cooler, wherein an internal quench mechanism is incorporated near the outlet of the first syngas cooler. Although not providing the same degree of heat recovery as described above, a single cooler system can decrease capital costs, facilitate downstream applications of the syngas that requires moisture in the syngas, while also mitigating fouling and plugging. However, incorporating an effective quench arrangement with a syngas outlet presents challenges, including how best to facilitate the quenching operation, while mitigating corrosion as well as sealing and controlling a differential pressure across portions of the syngas cooler heat transfer surfaces normally associated with such systems.